Broadly, the invention relates to wetting dry particles and dispersing the particles in a liquid. More specifically, the dry particles are wetted by dropping them into a liquid spout, and the spout carries the particles into an agitating liquid in which they are dispersed.
A line of high-molecular-weight, synthetic, water-soluble polymers are widely used as flocculating agents in the mining, pulp and paper, and chemical industries. One group of commercially available flocculating agents, which are sold under the name Separan, are comprised of polymers of acrylamide. In the use of these polymeric flocculating agents, it is a major problem to dissolve the dry particles in water. Problems have also been encountered in trying to dissolve certain types of clays, starches and natural gums in water or other liquids.
Referring particularly to the polymeric flocculating materials, in the dissolving operation the wetted particles have a tendency to agglomerate and form clumps. On the outer surfaces of each clump a gelatin-like layer is formed. The gelatin layer prevents wetting of the inner particles until the clump is dispersed in water, or some other solubilizing liquid. The sticky clumps are also difficult to handle because they frequently will plug up the mixing equipment.
Handling of the dry polymeric particles also presents another problem. Because of the extremely small size of the particles, they will frequently generate dust which is hazardous to breathe. In addition, the dust is a hygroscopic material which will combine with atmospheric moisture and form sticky coatings on walk-ways and equipment.
There are several known metods and apparatus for wetting and dispersing polymeric materials in a liquid medium. An example of a recent development in the art is the apparatus and method described in U.S. Pat. No. Re. 27681, to P. G. Gaddis.